This invention relates to a shaping apparatus for forming a single-fin sleeve from a wrapper sheet, particularly from a non-laminated aluminum foil in a packing machine for packaging articles, particularly confectionary items. The articles are continuously supplied to a conveying device by which they are advanced in a spaced relationship to one another.
Swiss Pat. No. 386,324 discloses a folding device for making a single-fin wrapper sleeve from a packaging sheet drawn from a supply roll. For making the side walls of the sleeve there are provided a guiding fork and a folding plate of U-shaped cross section. Both the guiding fork and the folding plate are supported on a carrier and are adjustable on all sides. Folding tongues with upwardly oriented guide horns are provided for forming the bottom surface of the sleeve. A folding device of this type is adapted to process relatively thick packing materials without difficulty. Currently used foils having a thickness of 1/100 mm, particularly non-laminated thermo-lacquered aluminum foils, however, have a tendency to buckle and tear if handled with such a folding apparatus.
An improvement in a folding apparatus of the above type is achieved by means of a forming (shaping) shoulder as disclosed, for example, in German Pat. No. 1,179,495. For making the forming shoulder a mandrel is surrounded by an externally tacky envelope which, in turn, is surrounded by a flexible foil such that one end of the foil is shaped to form a sleeve whereas the other end is of planar configuration. Thus, the shape of the foil is a sheet which runs together and then forms a sleeve. Then, the pocket formed by the foil is filled with a mass that hardens without shrinkage and after hardening of the mass the foil and the envelope are removed. The resulting body constitutes the desired shaping shoulder.
A very delicate packaging material such as the above-noted aluminum foil, however, places the most stringent requirements on packaging machines, such as a uniform and jar-free delivery speed, a gentle run-on as well as an accurate and sensitive regulation of the tensioning force. In addition, the forming device must have an optimal shape for making the sleeve, and there should be provided a removal transport device which can be synchronized with high accuracy with the run-on speed. Such packaging materials are used at the present time, for example, for wrapping chocolate bars. Thus, for reason of hygiene alone it is indispensable that the packaging material be free from torn portions.